We are seeing the increase in total no of people residing in urban areas throughout the world. Due to this sudden increase in urban population the respective governments are looking for ways to manage complexities, increase efficiencies and improve quality of life. This has created the need of the cities to promote the idea of sustainability with the advancement of the technology to monitor various processes of daily life & to regularize the infrastructure through smart solutions such as intelligent traffic monitoring, smart waste management, use of renewable source of energy for regular etc.
To propose a complete solution for a Smart City, we first need to understand the core processes involve in operating a regular city as a Smart City. To summarize, we can identify the functions involved in retrofitting, redevelopment & greenfield development with the processes like :
-Waste Management & Pollution Monitoring
-Transportation or Urban Mobility
-Municipal & Commercial Building Management
-Public Facilities Management
Dangers & Risks due to Lightning & Surges
The principle of a Smart City is to virtually observe, monitor, and operate various services while keeping a record of the same, it can be deduced that all these functions in a Smart City are completely dependent on the electrical and electronics system. Any building without the external lightning protection may get damaged due to the direct effect of lightning and even though your building is protected with External Lightning Protection, chances that your electrical & electronics system get damaged due to the surges is very likely because of the absence of Surge Protection devices. In this event due to the GPR known as Ground potential Rise during lightning, very high voltage surges travel through the ground to the equipment, which results into failure of the system, sometimes these surges have such high energy that it can cause the event of fire in the equipment the ground potential of the structure damage is eminent along with the equipment & machinery present in the building.
As per the latest Bureau of Indian Standard(NBC-2016) as well as from IS/IEC 62305 standard, any structure irrespective of the application & location, must be protected from the direct and indirect effect of lightning. As Smart City caters a large group of activities like Pharma, Traffic control, Waste Management, Water treatment it is mandatory to provide the suitable protection for the external structure as well as for all the equipment & machines present inside the campus. The necessity of the protection arrives as in case of failure to provide the recommended protection it can generate various losses as define in IEC 62305-2:
-Loss to human life
-Loss to service to public
-Loss of economic value
To minimize the damages & losses due to the lightning & surges, it is recommended to have the necessary External Lightning Protection as well as the required surge protection devices defined in the IEC 62305-4. These surge arresters protect the electrical & electronics devices from the effect of surges developed due to Ground Potential Rise(GPR).
Considering a complete infrastructure, we need to provide the Surge protection as per the NBC-2016 & IEC 62305-4 standard, as per which:
-The main incomer must have Type-1/Type-1+2 Surge arrester with Spark Gap protection which will arrest the lightning energy at the main entry of the power lines.
-All the Sub distribution boards should be given with separate protection of Type-2 SPD or as per the environmental situation. This situation is defined where power cable or communication cable travel from one structure to other in an open environment condition, then we must suggest Type-1 SPD even at SDB.
-Considering various communication equipment along with the telemetry system and centralized control room, from where all the equipment are being handled and controlled for their operations, one needs to select & provide the SPD w.r.t D1, C2 or C1 category as per the zones defined from the risk analysis.
Application in Smart City
As discussed above, Smart City is a group of different operations where each operation consists of multiple applications with Electrical & Electronics devices, to name a few operations are Water management system, Energy Management, Urban Mobility, Waste Management & E-Governance system. All these devices are prone to surges for which we need to provide the protection as per the specification requirement.
In reference to the Bureau of Indian Standard(NBC-2016) & IS/IEC 62305-4, we need to provide the protection at following levels of these application:
For Main Incomer Panel: It is recommended to have a Type 1+2 SPD in the main panel. According to this we can recommend our SPD with built-in fuse for overcurrent protection. Due to this integrated fuse, no external protection element i.e., fuse or MCB is required which further reduces the size & cost. This SPD also comes with mechanical indication as well as remote monitoring.
For Distribution Boards(DBs): As the distance of the sub-panel increases beyond 10mtr.from main incomer panel, the surges can be developed due to inductive effect, these are known as switching surges. To protect services from these switching surges, standard suggest providing a Type 2 SPD. Phoenix Contact recommend our VAL-SEC series. This SPD also have the mechanical indication along with also remote monitoring facility.
For Equipment: As Smart City have many equipment at different level with continuous requirement of power which makes them vulnerable to the surges. Type 3 SPD are generally installed right in front of the terminal device to be protected. The basic difference between Type-2 & Type-3 SPDs is that the requirement of nominal discharge capacity in Type-3 is significantly lower than the type-2 SPD. We can suggest our PLT-SEC series as per the requirement.
For Ethernet Protection: With Phoenix contact D-LAN-CAT series SPD we can provide the protection to services with various interface communication i.e., RJ-45, D-SUB9 up to 10Gbps data speed without any interruption in signal.
For Field Devices: For field devices like flow meter, Level & pressure meter Phoenix contact offers Surgetrab S-PT product which can be directly assembled on the field device. These SPDs comes with IP-67 protection. The recommendation can be done as per the requirement of end customer.
Equipotential Bonding: Earthing plays a very important role in the event of Lightning. As per IS-732 all protective, functional & lightning earthing needs to be interconnected, this coupling causes interference & surges in the communication equipment. To prevent this from happening we can provide Isolating Spark Gap(FLT-ISG product series) between Lightning Earthing & other earthing in campus, which creates an equipotential environment during the event of lightning, otherwise act as a passive device to avoid unwanted interference.
For Camera Protection: One of the biggest threats to the effective operation of your CCTV equipment is lightning strikes & electrical surges, if any of the camera in a system receive the surge from Lightning, all the camera in the system along with the monitoring controller will be affected due to this surge current. To protect the cameras with co-axial cable we can suggest our COAXTRAB series. The selection can be done as per the system available at client end.
Communication Devices For signals from Interface i.e., MODBUS, RS 485 communication Phoenix contact can offer Termitrab series surge protection with integrated status indicator and knife disconnection. These surge arresters can be used for HF applications and telecommunications interfaces. Phoenix contact have a complete series with the Ex & SIL certification.
Monitoring Devices for SPD We are providing these SPDs to protect the operation & working, it is necessary for us to monitor these SPDs whether they are in working condition or not. Phoenix Contact offers our Impulse check, which is a pulse measuring evaluation unit for the recording of surge currents and transient overvoltage over external sensor cables. Communication of the measured data is uploaded to PROFICLOUD via Ethernet. The data in the cloud can be accessed on the device via MODBUS/TCP service.